MAGNESIUM FERRITE WITH Sn~(4+) AND/OR Mo~(6+) SUBSTITUTIONS AS SENSING ELEMENT FOR ACETONE AND ETHANOL

摘要

In this paper we investigated the Mg ferrite with Sn~(4+) and/or Mo~(6+) substitutions as sensing element for two reducing gases, acetone and ethanol. The nominal compositions of the investigated samples are: MgFe_2O_4, Mg_(0.9)Sn_(0.1)Fe_2O_4, MgFe_(1.98)Mo_(0.02)O_4 and Mg_(0.9)Sn_(0.1)Fe_(1.98)Mo_(0.02)O_4. The samples were prepared by coprecipitation self combustion starting from metal nitrates. The structural properties were investigated by SEM and X-ray diffraction. Both Sn~(4+) and Mo~(6+) ions induce structural changes regarding grain sizes and porosity. The finest granulation, of about 100 nm, was observed in the Sn containing sample Mg_(0.9)Sn_(0.1)Fe_2O_4. The sensitivity measurements evidenced that the gas sensitivity depends on the ferrite composition, working temperature and test gas composition.